Eriopisella moretoni, Myers & Lowry & Barnes, 2018

Myers, A. A., Lowry, J. K. & Barnes, R. S. K., 2018, First record of the genus Eriopisella Chevreux, 1920 (Crustacea, Amphipoda, Senticaudata, Eriopisidae) from Australia, with the description of a new species, Eriopisella moretoni sp. nov., Zootaxa 4514 (2), pp. 256-262 : 257-259

Eriopisella moretoni sp. nov.

( Figs 1–3 )

Type Material: Holotype male 3.0 mm ( QM W53134), intertidal seagrass, 27°30'26"S 153°24'30"E, Deanbilla Bay , North Stradbroke Island, Moreton Bay, Queensland, R. S.K. Barnes, November 2017.

Other Material. 3 paratypes ( QM W53135) unsexed, same data as holotype .

Type locality. Moreton Bay , Queensland .

Etymology. The species is named after the type locality, Moreton Bay, Australia.

Description (based on holotype male, 3.0 mm).

Head. Head ocular lobes moderately produced, rounded; eyes not apparent in preserved material, but in life, observable as about four small black ommatidea on contiguous white pigment patches. Antenna 1 less than half body length; peduncular article 1 longer than article 2; article 3 about one third length of article 2; accessory flagellum rudimentary, scarcely observable; primary flagellum only a little longer than peduncle, with 10 weakly setiferous articles. Antenna 2 slender, about two thirds length of antenna 1; peduncular article 4 longer than article 5; flagellum not much longer than peduncular article 5, with 3 articles. Mandible weak; lacking palp. Maxilla 1 inner plate elongate, with two terminal setae; palp article 3 broad, spatulate. Maxilla 2 without oblique setal row. Labium mandibular projections rounded. Maxilliped palp article 2 broad, subovate.

Pereon. Gnathopod 1 coxa anterodistal margin strongly produced, rounded; basis slender, anterior margin weakly concave; merus expanded, spade-like; carpus and propodus subequal in length; propodus subovoid, palm oblique; dactylus much more than half length of propodus, distally sharp, overlapping palm. Gnathopod 2 coxa round; basis moderately slender, anterior margin substraight; carpus short, subtriangular, almost as broad as long; propodus longer than carpus, subovoid, palm long, very acute; dactylus long, two thirds length of propodus, fitting palm. Pereopods 3–4 dactylus elongate, subequal with propodus. Pereopods 5–7 in the length ratios 1:1.3:1.3. Pereopod 7 basis subovoid, posterior margin convex.

Pleon. Epimeron 2 posterodistal margin quadrate. Epimeron 3 posterodistal margin drawn out into a spine. Uropod 1 peduncle longer than rami, with strong basofacial robust seta and distolateral robust seta; rami subequal in length. Uropod 2 peduncle subequal in length with inner ramus; outer ramus a little shorter than inner. Uropod 3 peduncle short; inner ramus very short; outer ramus article 1 elongate, about 4 x as long as broad; second article short, less than one third length of article 1, slender, with two unequal, slender, apical setae. Telson divided to base, with three stout setae on the outer distal margin and three slender setae on the inner distal margin.

Female. Not sexually dimorphic.

Remarks. Eriopisella moretoni sp. nov. has relatively short antennae, no mandibular palp, gnathopod 1 with an unusual expanded spade-like merus and gnathopod 2 with a short broad carpus. Eriopisella moretoni sp. nov. differs from all other known species in the genus in having no mandible palp. In having a short antenna 1 with less than 12 articles in the primary flagellum, it differs from all other Eriopisella species except E. chieregoi Ruffo (other species have 17–20 articles), although in two species ( E. epimera Griffiths, 1974 and E. paraupolu Ortiz & Lalana, 1997 , this character state is unknown. Eriopisella moretoni sp. nov. differs from E. chieregoi and E. paraupolu Ortiz & Lalana in the subovoid propodus of gnathopod 1 and 2 (very long, slender and parallel-sided in E. chieregoi and E. paraupolu ). It differs from E. epimera Griffiths in having the second article on the outer ramus of uropod 3 about one third length of article 1 (about one tenth the length of the first article in E. epimera ). It also differs from E. chieregoi Ruffo , in having both rami with marginal robust setae (naked margins in E. chieregoi ).

Habitat. Intertidal seagrass. At the type locality it occurred at an overall density of 137 m -2 and formed the sixth most abundant member of the seagrass macrobenthos after the microgastropods Calopia imitata Ponder, 1999 and Pseudoliotia speciosa ( Angas, 1871) , brachyuran Enigmaplax littoralis Davie, 1993 , tanaid Longiflagrum

caeruleus ( Boesch, 1973) and amphipod Limnoporeia yarrague Barnard & Drummond, 1978 ( Barnes & Laurie, 2018). Distribution. Known only from the type locality.

Figures

FIGURE 1. Eriopisella moretoni sp. nov. male paratype, Stradbroke Island, Moreton Bay, Queensland.

FIGURE 2. Eriopisella moretoni sp. nov. male paratype, Stradbroke Island, Moreton Bay, Queensland.

FIGURE 3. Eriopisella moretoni sp. nov. male paratype, Stradbroke Island, Moreton Bay, Queensland.